Rechargeable lithium batteries are attractive energy storage devices for portable electric and electronic devices and electric and hybrid-electric vehicles because of their high specific energy compared to other electrochemical energy storage devices. A typical lithium cell contains a negative electrode, a positive electrode, and a separator located between the negative and positive electrodes. Both electrodes contain active materials that react with lithium reversibly. In some cases, the negative electrode may include lithium metal, which can be electrochemically dissolved and deposited reversibly.
Typically, during charging, electrons flow through an external circuit from the positive electrode to the negative electrode. Simultaneously, lithium ions deintercalate from the active material of the negative electrode to the electrolyte and intercalate from the electrolyte to the active material of the positive electrode. During discharging, opposite reactions occur.